calligrapher beetles

Calligrapha scalaris group is a species complex – an informal grouping – of leaf beetles in the genus Calligrapha. Many were previously included in the species Calligrapha scalaris.

There are fourteen species recognized as the Calligrapha scalaris group. All of them occur in North America north of Mexico. Seven species have been recorded in Minnesota.

Like all calligrapher beetles, species in this group are found in woodlands. Adults are active from April to September.

Both adults and larvae feed on the leaves of trees and shrubs. Some feed exclusively on a single tree or shrub genus or even just a single species. Some will move to a secondary host if their preferred host is unavailable.

Two characters distinguish species in the Calligrapha scalaris group from similar Calligrapha species. Both characters must be present.

On each elytron:

1. The subsutural stripe merges with the sutural stripe.
   
 
2. When the arcuate band is divided into two separate spots, the subsutural stripe merges usually with the basal spot, sometimes with the top spot, sometimes with both. The only exception is Calligrapha spiraea, in which both spots are free.

Sources

24, 27, 29, 30, 82, 83.

New distribution records and biogeography of Calligrapha species in North America (Coleoptera: Chrysomelidae, Chrysomelinae) Gómez-Zurita J. 2005. Canadian Field-Naturalist 119: 88-100.

Tribe
Some sources place the genus Calligrapha in the tribe Chrysomelini, others sources place it in the tribe Doryphorini.

Species group
The species Calligrapha scalaris was first described by John Eatton LeConte in 1824 on the basis of color and two conspicuous markings on the wing covers (elytra): a moon-shaped marking in the shoulder (humeral) area; and a broad, tooth-like marking connected to the middle (sutural) stripe. The beetle was reported to be an occasional serious pest of American elm. LeConte’s description accurately distinguished the new species from all other Calligrapha species then known. Since then, at least thirteen new species have been described that share these characters.

In 1945, W. J. Brown identified a species complex of several species that were morphologically very similar but had very different host preferences and ecologies. A more recent study (Gómez-Zurita J., 2015) analyzed the original material from the Calligrapha scalaris collections of LeConte (1824) and of G. H. Horn (1884). The author found the collections contained as many as nine distinct species, many having no association with elm. He redefined the original species and defined fourteen species as the “Calligrapha scalaris” group.

Location: Lake Shore, MN

I came across this picture on a memory card from last year. Just this one beetle and never saw it again. On our deck railing.